German Published Patent Appln. No. 2 158 117 describes an internal combustion engine having throttle control, in which an injection device injects fuel into the intake manifold leading into a combustion chamber of the internal combustion chamber; the fuel is heated by an electrical fuel heater prior to the injection, in order to improve the evaporation of the fuel following the injection. In this particular case, an Otto engine having intake manifold injection is involved, which is operated using a gasoline-based fuel.
In addition, from German Published Patent Appln. No. 10 2009 000 894, for example, it is known to operate internal combustion engines not only using gasoline-based fuels, but to supply them also with alternative fuels such as (bio)ethanol, compressed gas (CNG, Compressed Natural Gas) or liquid gas (LNG, Liquefied Natural Gas), either additionally or exclusively. However, considerable cold start problems arise when using fuels of this type. Especially when using a fuel made up to 100% of bio-ethanol, considerable startup difficulties occur already at a temperature limit of approximately 15° C., depending on the individual engine characteristics, so that high exhaust-gas rates are produced in the cold start phase in addition.